This invention relates to pulleys and, more particularly, to an idler pulley assembly comprising a first bell end portion having a first inward-facing face and a cylindrical shaft extending outward therefrom and perpendicular thereto; a second bell end portion having a second inward-facing face disposed at the end of the cylindrical shaft perpendicular thereto and parallel to the first inward-facing face, the second bell end portion being connected to the first bell end portion; and, a hub rotatingly mounted on the cylindrical shaft between the first inward-facing face and the second inward-facing face.
Pulleys in general are well known in the art. A pulley may be mounted on a driven shaft to impart movement to a drive belt passing over the pulley. Similarly, a pulley may be mounted on a drive shaft to impart movement to the drive shaft from a drive belt passing over the pulley. A so-called idler pulley as depicted in FIG. 1 is employed to simply guide a drive belt passing over the pulley. The idler pulley assembly 10 of FIG. 1 is typical and comprises a mounting bracket 12 having a pair of bearings 14 therein. An idler shaft 16 passes through the bearings 14 and is held in place by a pair of retaining rings at 18. The idler pulley 20 itself is mounted on the idler shaft 16 and held in place by a set-screw 22. Note that the idler pulley 20 also includes a pair of guide ridges 24 along the periphery thereof between which a belt (not shown) can ride without working its way off. This configuration is employed with flat belts whereas so -called V-belts have V-shaped grooves in the pulleys which are not prone to belt loss from lateral movement as would occur with a flat belt on a flat pulley without the guide ridges 24.
As can be appreciated, the idler pulley assembly 10 of FIG. 1 is complex and, therefore, time consuming and costly to make and install in proper alignment. Not counting the mounting bracket, there are seven individual pieces to manufacture and then assemble.
Various attempts at improving pulleys and idler pulleys have been proposed over the years. For example, the 1986 patent to Molloy et al. (U.S. Pat. No. 4,571,226) discloses an idler pulley assembly in which the two halves of a V-belt idler pulley are made of plastic and snap together over a single ball-bearing. Idler pulleys of plastic wherein the two sides are fastened together are also disclosed in Horsey (U.S. Pat. No. 3,633,432) and Boyer et al. (U.S. Pat. No. 4,193,310). A unitary pulley having the guide ridges formed therein is disclosed in Cameron (U.S. Pat. No. 4,012,961), Chadborne (U.S. Pat. No. 2,924,431), Peura (U.S. Pat. No. 3,785,217), Walter et al. (U.S. Pat. No. 4,610,646), Van Deventer III (U.S. Pat. No. 2,760,378), Rauscher (U.S. Pat. No. 4,034,616), and Allen (U.S. Pat. No. 4,820,426). Pulley construction is also shown in McCutchan, Jr. (U.S. Pat. No. 4,473,363), Allen (U.S. Pat. No. 4,906,223), and Kovaleski (U.S. Pat. No. 4,441,692). While each of the foregoing patents discloses some improvement to pulley construction for certain purposes, none provides a simple structure accomplishing the objects of the basic idler pulley assembly 10 of FIG. 1 which is not time consuming and costly to make and install in proper alignment.
Wherefore, it is an object of the present invention to provide an idler pulley assembly which consists of only three parts.
It is another object of the present invention to provide an idler pulley assembly which only employs parts which are made quickly and inexpensively of injection molded plastic.
It is still another object of the present invention to provide an idler pulley assembly which has only one moving part.
It is yet another object of the present invention to provide an idler pulley assembly in which the hub over which a flat belt rides does not require integral guide ridges to prevent side loss of the belt.
It is a still further object of the present invention to provide an idler pulley assembly which requires no tools for installing, removal, or alignment.
Other objects and benefits of the invention will become apparent from the detailed description which follows hereinafter when taken in conjunction with the drawing figures which accompany it.